LIBRARY 

OF  THE 

UNIVERSITY  OF  CALIFORNIA. 

RECEIVED    BY    EXCHANGE 


Class 


The   Osmotic   Pressure  of 
Cane    Sugar    Solu- 
tions at  10°. 


DISSERTATION 


SUBMITTED    TO    THE    BOARD    OF    GRADUATE    STUDIES    OF 

THE   JOHNS    HOPKINS  'UNIVERSITY  IN  CONFORMITY 

WITH  THE  REQUIREMENTS  FOR  THE  DEGREE 

OF  DOCTOR  OF  PHILOSOPHY. 


BY 


HARMON  V.  MORSE. 


1908 


E ASTON,  PA.  : 

ESCHENBACH    PRINTING    COMPANY. 
1908 


The   Osmotic   Pressure  of 
Cane    Sugar    Solu- 
tions at  10°. 


DISSERTATION 


SUBMITTED   TO   THE   BOARD    OF    GRADUATE    STUDIES    OF 

THE  JOHNS   HOPKINS   UNIVERSITY  IN  CONFORMITY 

WITH  THE  REQUIREMENTS  FOR  THE  DEGREE 

OF  DOCTOR  OF  PHILOSOPHY. 


BY 


HARMON  V.  MORSE. 


EASTON,  PA.  : 

ESCHENBACH  PRINTING  COMPANY. 
1908 


CONTENTS. 


Acknowledgment 4 

Introduction 5 

Sources  of  Error 6 

I.  Thermometer  Effects 7 

II.  Displacement  of  the  Manometer 7 

III.  Dilution  of  the  Cell  Contents v.    8 

Series  I 10 

Record  of  Experiments 1 1 

Summary  of  Results 17 

Discussion  of  Results 19 

Series  II , 21 

Record  of  Experiments 23 

Summary  of  Results 33 

Discussion  of  Results 35 

Concordance  of  Results 38 

Molecular  Ratios 38 

Temperature  Coefficient 39 

Biography 42 


186960 


ACKNOWLEDGMENT. 

The  writer  wishes  to  express  his  appreciation  of  the  in- 
struction received  in  the  laboratory  and  lecture  room  from 
President  Remsen,  Professor  Morse,  Professor  Jones,  Pro- 
fessor Renouf,  Professor  Clarke,  Associate-Professor  Acree, 
Dr.  Tingle  and  Associate-Professor  Swartz. 

Especially  does  he  appreciate  the  careful  and  thorough 
training  received  with  Professor  Morse,  under  whom  this 
investigation  has  been  pursued. 


OF  THE  V 

UNIVERSITY  I 


.m.<\V 


The  Osmotic  Pressure  of  Cane 
Sugar  Solutions  at  10°. 


INTRODUCTION. 

Determinations  of  the  osmotic  pressures  of  cane  sugar 
solutions  in  the  vicinity  of  o0,1  4°,2  and  20°  3  have  been 
carried  out  in  the  past  few  years  in  this  laboratory  by  H. 
N.  Morse  and  his  co-workers  which  have  developed  the 
following  facts : 

I.  The  pressures  obtained  at  the  two  limiting  tempera- 
tures thus  far  investigated,  i.  e.,  at  o°  and  at  20°  vary  only 
slightly. 

II.  At   the    intermediate   temperature,    4°,    the    osmotic 
pressure  is  practically  the  same  as  at  o°  and  at  20°. 

It  was  stated  regarding  the  series  at  o°:  "Others  may 
discover  in  the  high  pressures  in  question,  and  in  the  fact 
that  they  are,  in  a  general  way,  nearly  equal  to  those  which 
were  obtained  in  the  vicinity  of  20°,  a  suggestion  that  os- 
motic pressure,  unlike  that  of  gases,  has  little  or  no  temperature 
coefficient.  But  an  equally  just  suspicion,  apparently, 
is  that  somewhere  between  o°  and  20°  a  temperature  may 
be  found  at  which  osmotic  pressure,  like  the  volume  of 
the  solvent,  is  at  a  minimum,  and  from  which  it  increases, 
with  change  of  temperature  in  both  directions."4 

No  minimum  having  been  found  in  the  vicinity  of  4°, 
two  other  intermediate  temperatures,  namely,  10°  and 
I5°5,  were  selected  in  order  to  ascertain  whether,  at  either 
of  these,  there  might  be  a  minimum  in  osmotic  pressure, 
also  for  the  purpose  of  throwing  more  light  on  the  question 
of  the  deviation  of  osmotic  from  gas  pressure,  i.  e.,  upon 

1  Am.  Chem.  J.,  37,  425. 

2  Ibid.,  38,  175. 

3  Ibid.,  36,  39. 

4  Ibid.,  J.,  37,  466. 

5  Ibid.,  40, 


the  question  of  the  temperature  coefficient  of  osmotic  pres- 
sure. 

As  a  result  of  the  work  at  10°,  two  series  of  measurements 
are  given  in  this  dissertation.  The  first  of  these  was  carried 
out  in  the  Spring  of  1907  under  the  same  general  conditions 
as  in  the  previous  measurements  in  the  vicinity  of  o°  and 
4°.  Consequently,  they  are  subject  in  some  degree  to  the 
uncertainties  regarding  the  actual  magnitude  of  the  osmotic 
pressures  which  have  been  pointed  out  from  time  to  time 
in  connection  with  the  earlier  work. 

It  has  been  customary  to  make  duplicate  determinations 
of  the  osmotic  pressure  of  ten  concentrations  of  the  solution 
ranging  between  o.i  and  i.o  weight-normal.  In  this  respect, 
Series  I.  is  incomplete  because,  while  the  work  was  in  progress, 
important  improvements  in  the  method  were  introduced 
which  made  it  desirable  to  repeat  the  whole  work  under 
the  more  advantageous  conditions.  Nevertheless,  the  re- 
sults obtained  in  the  earlier  work  are  given  as  having  some 
value  in  connection  with  the  general  problem  of  osmotic 
pressure. 

The  measurements  given  in  Series  II.  were  all  made  under 
the  improved  conditions  referred  to  above. 

In  order  to  make  clear  the  character  of  the  improvements 
in  method  which  were  introduced  and  which  made  a  repeti- 
tion of  the  earlier  measurements  desirable,  there  is  intro- 
duced here  a  brief  statement  of  the  sources  of  error  which 
had  been  encountered  in  the  determination  of  osmotic  pres- 
sure. 

SOURCES  OF  ERROR. 

The  larger  sources  of  error  which  have  been  encountered 
in  the  attempt  to  measure  osmotic  pressure  are:  (i)  "ther- 
mometer effects;"  (2)  upward  displacement  of  the  manom- 
eter while  in  the  closed  cell,  with  more  or  less  distortion 
of  the  rubber  stopper;  (3)  the  dilution  of  the  cell  contents. 

The  minor  source  of  error  which  may  be  mentioned  in 
this  connection  was  the  slow  diminution  of  the  air  volume 
in  the  manometer. 


(i)    Thermometer  Effects. 

When  the  temperature  of  the  bath  rises,  the  solution  within 
the  cell  expands  more  rapidly,  and  to  a  greater  extent, 
than  the  cell  itself.  This  expansion  of  the  liquid  causes 
water  to  be  expelled  from  the  solution  through  the  membrane 
and  is  attended  by  a  concentration  of  the  solution.  If  the 
passage  of  the  water  through  the  membrane  is  not  sufficiently 
rapid,  as  it  usually  is  not,  there  is  created  an  abnormally 
high  pressure  which,  if  the  rise  in  temperature  is  rapid, 
may  considerably  exceed  the  true  osmotic  pressure  of  the 
solution. 

On  the  other  hand,  if  the  temperature  of  the  bath  falls, 
the  solution  contracts  more  rapidly  than  the  containing 
cell,  and  water  passes  through  the  membrane  in  the  reverse 
direction.  If  this  passage  from  the  outer  vessel  to  the  solu- 
tion within  the  cell  is  not  rapid  enough  to  neutralize  the 
shrinkage  of  the  solution,  there  is  established  an  abnor- 
mally low  pressure. 

In  the  first  series  of  measurements  of  osmotic  pressure 
the  thermometer  effects  were  large  and  the  results  were 
correspondingly  inexact. 

The  methods  of  maintaining  comparatively  constant  tem- 
peratures in  the  bath  were,  however,  improved  as  the  work 
progressed  until,  when  the  investigation  in  Series  II.  was 
undertaken,  it  was  practicable  to  maintain,  throughout 
a  measurement  of  pressure,  temperatures  which  did  not 
vary  more  than  0.2°. 

(2)    Displacement   of    the   Manometer    and   Distortion  of  the 

Rubber  Stopper. 

The  upward  displacement  of  the  manometer  under  pres- 
sure, with  the  accompanying  distortion  of  the  rubber  stopper 
which  holds  the  manometer  and  closes  the  cell,  is  attended 
by  an  increase  in  the  capacity  of  the  cell  and  a  corresponding 
dilution  of  the  solution.  The  first  two  series  of  measure- 
ments of  the  osmotic  pressure  of  cane  sugar  solutions,  i.  e., 
in  the  vicinity  of  20  °,1  also  the  first  series  of  measurements 

i  Am.  Chem.  J.,  36,  50;  37,  328,  460. 


8 

of  glucose  solutions,1  were  considerably  affected  by  this 
source  of  dilution,  but  in  the  succeeding  series  effective 
measures  were  devised  for  rendering  the  stoppers  so  rigid 
in  their  places,  that  the  upward  movements  of  the  manom- 
eters became  quite  insignificant. 

In  the  present  work — Series  II. — the  greatest  displace- 
ment of  the  manometer  during  a  measurement  was  1.29 
mm.  while  the  average  displacement  amounted  to  only 
0.3  mm. 

(3)   Dilution  of  the  Cell  Contents. 

One  source  of  dilution  in  the  cell  contents  has  been  men- 
tioned above.  This  would  have  been  of  little  importance 
if  it  had  been  the  only  source  of  dilution  because  it  is  known 
to  precede  the  measurement  of  pressure  and  can  be  corrected 
for,  if  uncomplicated  with  dilution  which  is  subsequent 
to  the  measurement  of  pressure. 

There  is,  however,  another  source  of  dilution  in  the  water 
which  fills  the  cell  wall2  at  the  time  of  closing  and  opening 
the  cell.  If  the  contents  of  the  cell  are  at  any  time  during 
these  operations  under  diminished  pressure,  the  water  is 
sucked  in  from  the  porous  wall  through  the  membrane, 
and  the  solution  is  diluted.  The  dilution  due  to  this  cause, 
which  occurs  while  the  cell  is  being  closed,  precedes  the 
measurement  of  pressure,  and  a  correction  should  be  made 
for  it;  but  the  dilution  due  to  diminished  pressure,  which 
occurs  while  the  cell  is  being  opened,  is  subsequent  to  the 
measurement  and  must  be  neglected. 

Unfortunately,  there  was  no  possibility  of  ascertaining 
how  much  of  the  total  observed  dilution  occurred  at  either 
of  these  periods.  In  other  words,  it  was  not  practicable 
to  determine  how  much  of  the  total  dilution  should  be  cor- 
rected for,  and  how  much  should  be  neglected. 

A  partial  remedy  for  dilution  due  to  the  sucking  in  of 
water  from  the  cell  wall,  while  closing  and  opening  the  cell, 
was  found  in  the  process  of  dipping3  the  cell,  after  filling 

1  Am.  Chem.  J.,  36,  23. 

2  Ibid.,  36,  26,  49;  37,  589. 

3  Ibid.,  37,  464,  584. 


with  the  solution,  in  another  solution  of  equal  or  somewhat 
greater  concentration;  also  in  a  more  rapid  and  careful 
manipulation.  The  improvement  effected  in  this  way 
is  to  be  seen  in  the  diminishing  "total  dilution"  in  the  suc- 
ceeding series  of  measurements  of  the  osmotic  pressure 
of  cane  sugar  solutions. 

In  the  first  series  in  which  the  polariscope  was  used — 
that  in  the  vicinity  of  20°  l — the  average  amount  of  dilution 
was  2.8  per  cent.  In  the  second — that  at  o°  2 — it  was  1.47 
per  cent,  while  in  the  third — that  at  4°  3 — it  was  1.28  per 
cent. 

The  proper  distribution  of  this  dilution  in  the  correction 
of  the  results  has  been  much  discussed4  in  the  various  papers 
on  osmotic  pressure  which  have  appeared  from  this  laboratory. 

It  was  concluded  that  not  less  than  half  of  the  total  di- 
lution must  occur  while  the  cells  are  being  opened,  because, 
during  that  period,  the  contents  are,  for  a  longer  time,  and 
more  continuously,  subjected  to  diminished  pressure  than 
while  the  cells  are  being  closed.  The  plan  was,  therefore, 
adopted  for  a  time  of  correcting  the  results  for  only  one- 
half  of  the  observed  dilution.  Later,  when  a  cell  was  to  be 
opened,  the  stopper  was  pierced  by  a  hypodermic  needle 
which  brought  the  cell  contents  at  once  under  atmospheric 
pressure  and  prevented  any  diminution  of  that  pressure 
during  the  removal  of  the  stopper  and,  consequently,  any 
dilution  of  the  solution. 

It  was  found  after  introducing  this  modification  of  earlier 
practice  that  there  was  very  little,  and  frequently  no,  di- 
lution whatever  of  the  cell  contents.  In  the  majority  of 
cases  the  solutions  when  removed  from  the  cells  exhibited 
the  same  rotation  as  the  original  solutions,  showing  that 
in  neglecting  one  half  of  the  loss  in  rotation,  the  results  of 
earlier  series  had  been  overcorrected  rather  than  under- 
corrected  for  dilution. 

1  Am.  Chem.  J.(  36,  39. 

2  Ibid.,  37,  425. 

3  Ibid.,  38,  175. 

4  Ibid.,  34,  30,  92;  36,  40,  48;  37,  427,461;  38,  177,  199. 


10 

It  was  this  elimination  of  practically  all  the  dilution  of 
the  cell  contents  which  caused  the  writer  to  undertake 
Series  II.  of  the  measurements  presented  in  this  dissertation. 

SERIES  I. 

As  has  been  stated,  the  measurements  belonging  to  this 
Series  were  carried  out  during  April  and  May,  1907,  be- 
fore methods  were  devised  for  the  suppression  of  practically 
all  dilution  and  for  the  exact  control  of  temperature  con- 
ditions. At  the  same  time  they  are  as  accurate  as  those 
determinations  in  the  vicinity  of  4°  and  agree  with  the 
general  relations  of  osmotic  to  gas  pressure  established 
in  the  earlier  work. 

The  pressures  of  two  of  the  concentrations — the  0.8  and 
0.9  normal — were  not  measured,  time  not  permitting.  Nor 
were  duplicate  measurements  made  in  the  majority  of  cases 
for  the  same  reason. 


II 

Table  I. 

p.i  Wt.  normal  solution.  Exp.  No.  i.  Rotation:  (i) 
original,  i2°.6;  (2)  at  conclusion  of  Exp.,  i2°.6;  loss,  o°  =  o 
per  cent.  Manometer:  No.  13;  volume  of  air,  435.09;  dis- 
placement, 0.02  mm.  Cell  used,  D.  Resistance  of  membrane, 
550,000.  Corrections:  (i)  atmospheric  pressure,  i.oo;  (2) 
liquids  in  manometer,  0.48;  (3)  dilution,  o;  (4)  concentration, 
o;  (5)  capillary  depression,  0.02.  Initial  pressure,  1.99. 
Time  of  setting  up  cell,  4.30  P.M.,  Apr.  20,  1907. 

Temperature.  Pressure. 


Time. 

Solution. 

Manometer. 

air.        Osmotic. 

Gas.  Difference. 

April  21. 

2.  30  P.M. 

9° 

•4 

10° 

.0 

148 

.24 

2 

•43 

2 

•30 

0.13 

8.00  P.M. 

9° 

•5 

10° 

•  25 

148 

.07 

2 

•44 

2 

•30 

O.I4 

April  22. 

8.30  A.M. 

9° 

.6 

10° 

•3 

148 

.14 

2 

•44 

2 

•31 

0.13 

2.44    2.30    0.14 
Molecular  osmotic  pressure,  24.40. 
Molecular  gas  pressure,  23 .03. 
Ratio  of  osmotic  to  gas  pressure,  1.059. 

Table  II. 

o.i  Wt.  normal  solution.  Exp.  No.  2.  Rotation:  (i)  origi- 
nal, 12°. 6;  (2)  at  conclusion  of  Exp.,  12°. 5;  loss,  o°. 1=0.79 
per  cent.  Manometer:  No.  n;  volume  of  air,  465.94;  dis- 
placement, 0.02  mm.  Cell  used,  B.  Resistance  of  membrane, 
550,000.  Corrections:  (i)  atmospheric  pressure,  i.oo;  (2) 
liquids  in  manometer,  0.40;  (3)  dilution,  o.oi ;  (4)  concen- 
tration, o;  (5)  capillary  depression,  0.02.  Initial  pressure, 
1.89.  Time  of  setting  up  cell,  4.30  P.M.,  Apr.  20,  1907. 

Temperature.  Pressure. 

Volume  . — 


Time.  Solution.  Manometer.  air.      Osmotic.    Gas.    Difference. 
April  21. 

2.30  P.M.  9°. 4  10°. o  154.68     2.42     2.30     0.12 

S.ooP.M.  9°. 5     10°. 25  154-54     2.43     2.30     0.13 

April  22. 

9.00P.M.  9°. 7  10°. 4  I53-92     2.44     2.31     0.13 


2.43     2.30     0.13 

Loss  in  rotation  corrected  as  inversion. 
Molecular  osmotic  pressure,  24.30. 
Molecular  gas  pressure,  23.03. 
Ratio  of  osmotic  to  gas  pressure,  1.055. 


12 

Table  III. 

0.2  Wt.  normal  solution.  Exp.  No.  i.  Rotation:  (i) 
original,  24°. 9;  (2)  at  conclusion  of  Exp.,  240.y;  loss,  o°.2=o.8 
per  cent.  Manometer:  No.  21;  volume  of  air,  477.75;  dis- 
placement, 0.3  mm.  Cell  used,  H.  Resistance  of  membrane, 
280,000.  Corrections:  (i)  atmospheric  pressure,  0.99;  (2) 
liquids  in  manometer,  0.47;  (3)  dilution,  0.02;  (4)  concen- 
tration, o;  (5)  capillary  depression,  0.02.  Initial  pressure, 
3.81.  Time  of  setting  up  cell,  4.00  P.M.,  Apr.  22,  1907. 

Temperature.  Pressure. 


Time.             Solution 

.    Manometer. 

air.        Osmotic.    Gas 

.    Difference. 

April  22. 

8.00  P.  M. 

10°, 

,2 

10° 

.2 

89 

.78 

4 

78 

4 

.62 

o.  16 

April  23. 

8.30  A.M. 

10° 

O 

10° 

.8 

89 

•97 

4 

78 

4 

.62 

o.  16 

2.00  P.M. 

9° 

9 

10° 

.8 

90 

.19 

4- 

77 

4 

,61 

o.  16 

4.78     4.62     0.16 

Loss  in  rotation  corrected  as  inversion. 
Molecular  osmotic  pressure,  23.90. 
Molecular  gas  pressure,  23.10. 
Ratio  of  osmotic  to  gas  pressure,  1.035. 

Table  IV. 

0.3  Wt.  normal  solution.  Exp.  No.  i.  Rotation:  (i)  original, 
36°. 6;  (2)  at  conclusion  of  Exp.,  36°. 25;  loss,  o°. 35  =0.96 
per  cent.  Manometer:  No.  n;  volume  of  air,  465.94;  dis- 
placement, 0.4  mm.  Cell  used,  B.  Resistance  of  membrane, 
276,000.  Corrections:  (i)  atmospheric  pressure,  0.99;  (2) 
liquids  in  manometer,  0.53;  (3)  dilution,  0.05;  (4)  concentra- 
tion, o;  (5)  capillary  depression,  0.02.  Initial  pressure,  6.10. 
Time  of  setting  up  cell,  4.00  P.M.,  Apr.  23,  1907. 

Temperature.  Pressure. 

Volume 


Time.  Solution.  Manometer.          air.  Osmotic.  Gas.    Difference. 
April  24. 

8.00A.M.  10°. 2  11°. O  61.00         7.15  6.93       0.22 

2.00P.M.  10°.  I  II°.0  60.93         7.16  6.93      0.23 

5.OO  P.M.  10°. 2  11°. 2  6l.03         7-T4  6.93       0.21 


7.15       6.93      0.22 

Loss  in  rotation  corrected  as  inversion. 
Molecular  osmotic  pressure,  23.87. 
Molecular  gas  pressure,  23.10. 
Ratio  of  osmotic  to  gas  pressure,  1.032. 


13 

Table  V. 

0.3  Wt.  normal  solution.  Exp.  No.  2.  Rotation:  (i)  original, 
36°. 6;  (2)  at  conclusion  of  Exp.,  36°.4;loss,  o°.2=o.55  per 
cent.  Manometer:  No.  21;  volume  of  air,  477.75;  displace- 
ment, 0.34  mm.  Cell  used,  B.  Resistance  of  membrane, 
183,000.  Corrections:  (i)  atmospheric  pressure,  0.99;  (2) 
liquids  in  manometer,  0.50;  (3)  dilution,  0.03;  (4)  concentra- 
tion, o;  (5)  capillary  depression,  0.02.  Initial  pressure,  5.67. 
Time  of  setting  up  cell,  5.00  P.M.,  Apr.  u,  1907. 

Temperature.  Pressure. 


Time. 

Solution.    Manometer, 

•          VVlUUJ.t 

air. 

Osmotic. 

Gas.    Difference. 

April  12. 

9.00  P.M. 

10° 

.0 

11° 

.0 

62 

.22 

n 

.18 

6.92 

0 

.26 

April  13. 

9.OO  P.M. 

9° 

•4 

10° 

.0 

62 

•17 

n 

.18 

6.91 

,  0 

.27 

April  14. 

4.00  P.M. 

9° 

.2 

10° 

.0 

62 

.02 

7' 

19 

6.91 

0 

,28 

7.18     6.92     0.27 

Loss  in  rotation  corrected  as  inversion. 
Molecular  osmotic  pressure,  23.94. 
Molecular  gas  pressure,  23.04. 
Ratio  of  osmotic  to  gas  pressure,  1.038. 

Table  VI. 

0.4  Wt.  normal  solution.  Exp.  No.  i.  Rotation:  (i) 
original,  48°.o;  (2)  at  conclusion  of  Exp.,  47°.6; ,  loss  o°.4  =  o.83 
per  cent.  Manometer:  No.  21;  volume  of  air,  477.75;  dis- 
placement, 0.05  mm.  Cell  used,  G.  Resistance  of  membrane, 
158,000.  Corrections:  (i)  atmospheric  pressure,  i.oo;  (2) 
liquids  in  manometer,  0.52;  (3)  dilution,  0.06;  (4)  concen- 
tration, o;  (5)  capillary  depression,  0.02.  Initial  pressure, 
8.40.  Time  of  setting  up  cell,  4.00  P.M.,  Apr.  17,  1907. 

Temperature.  Pressure. 

Volume     . — 


Time.  Solution.  Manometer.  air.  Osmotic.  Gas.    Difference. 
April  18. 

8.30A.M.        9°. 3     10°. 4  47-82     9.47  9.21     0.26 

2.00P.M.        9°. 6     io°-5  47-74     9-47  9-22     0.25 

5-oop.M.        9°. 6     10°. 65  47-8i     9.4?  9-22     0.25 


9.47     9.22     0.25 

Loss  in  rotation  corrected  as  inversion. 
Molecular  osmotic  pressure,  23.68. 
Molecular  gas  pressure,  23.04. 
Ratio  of  osmotic  to  gas  pressure,  1.027. 


14 

Table  VII. 

0.5  Wt.  normal  solution.  Exp.  No.  i.  Rotation:  (i) 
original,  58°. 9;  (2)  at  conclusion  of  Exp.,  58°. 2;  loss,  o°.7  =  i.i9 
per  cent.  Manometer:  No.  21;  volume  of  air,  477.75;  dis- 
placement, o.oi  mm.  Cell  used,  O.  Resistance  of  membrane, 
278,000.  Corrections:  (i)  atmospheric  pressure,  0.98;  (2) 
liquids  in  manometer,  0.53;  (3)  dilution,  o.io;  (4)  concen- 
tration, o;  (5)  capillary  depression,  0.02.  Initial  pressure, 
11.66.  Time  of  setting  up  cell,  4.00  P.M.,  Apr.  9,  1907. 


Temperature. 

olume 

Pressure. 

Time. 

Solution.  Manometer. 

air. 

Osmotic. 

Gas.    Difference. 

April 

10. 

11.00 

A.M. 

9° 

-85 

10° 

.2 

38 

•85 

II 

.90 

n-54 

0.36 

4-OO 

P.M. 

9°- 

6 

10°. 

7 

38 

.88 

II 

.89 

H-53 

0.36 

April 

ir. 

8.00 

A.M. 

9° 

.8 

10°. 

3 

38 

.82 

II 

.90 

n-53 

0-37 

11.90    11.53    0-36 

Loss  in  rotation  corrected  as  inversion. 
Molecular  osmotic  pressure,  23.79. 
Molecular  gas  pressure,  23.07. 
Ratio  of  osmotic  to  gas  pressure,  1.032. 

Table  VIII . 

0.5  Wt.  normal  solution.  Exp.  No.  2.  Rotation:  (i) 
original,  58°. 9;  (2)  at  conclusion  of  Exp.,  58°.!;  loss,  o°.8  =  1.36 
per  cent.  Manometer:  No.  6;  volume  of  air,  396.89;  displace- 
ment, 0.09  mm.  Cell  used,  G.  Resistance  of  membrane, 
183,000.  Corrections:  (i)  atmospheric  pressure,  0.98;  (2) 
liquids  in  manometer,  0.66;  (3)  dilution,  0.12;  (4)  concen- 
tration, o;  (5)  capillary  depression,  0.02.  Initial  pressure, 
12.02.  Time  of  setting  up  cell,  4.00  P.M.,  Apr.  8,  1907. 

Temperature.  Pressure. 

Volume 


Time.  Solution.  Manometer.             air.  Osmotic.  Gas.    Difference. 
April  9. 

9.00P.M.  10°. 2       11°. 2  32.21  11.91  11-55      0-36 
April  10. 

9.00  A.M.  io°.o     10°. 5  32.28  11.89  n   54     0-35 

I.OOP.M.  9°. 6     10°. 3  32-30  n-88  11.53     0-35 


11.89     n-54     0-35 
Loss  in  rotation  corrected  as  inversion. 
Molecular  osmotic  pressure,  23.79. 
Molecular  gas  pressure,  23.08. 
Ratio  of  osmotic  to  gas  pressure,  1.031. 


15 

Table  IX. 

0.5  Wt.  normal  solution.  Exp.  No.  3.  Rotation:  (i) 
original,  58°.9;  (2)  at  conclusion  of  Exp.,  58 °4;  loss,  o°.5=o.85 
per  cent.  Manometer:  No.  5;  volume  of  air,  434.98;  displace- 
ment, 0.04  mm.  Cell  used,  D.  Resistance  of  membrane, 
275,000.  Corrections:  (i)  atmospheric  pressure,  0.98;  (2) 
liquids  in  manometer,  0.64;  (3)  dilution,  0.07;  (4)  concen- 
tration, o;  (5)  capillary  depression,  0.02.  Initial  pressure, 
12.98.  Time  of  setting  up  cell,  4.00  P.M.,  Apr.  8,  1907. 

Temperatxtre.  Pressure. 


Time. 

Solution.  Manometer. 

V  U1UILIC 

air. 

Osmotic. 

Gas 

.    Difference. 

April  9. 

9.OO  P.M. 

10°. 

2 

11°. 

2 

35 

.08 

12 

.02 

II 

•55 

0-47 

April  10. 

II.OO  A.M. 

9° 

.85 

10° 

.2 

35 

,14 

II 

•99 

II 

•54 

0-45 

4-00  P.M. 

9° 

6 

10°. 

45 

35 

i? 

II 

.98 

II 

•53 

0-45 

12.00       11-54      0.46 

Loss  in  rotation  corrected  as  inversion. 
Molecular  osmotic  pressure,  23.99. 
Molecular  gas  pressure,  23.08. 
Ratio  of  osmotic  to  gas  pressure,  1.040. 

Table  X. 

0.6  Wt.  normal  solution.  Exp.  No.  i.  Rotation:  (i) 
original,  69°4;  (2)  at  conclusion  of  Exp.,  68°. 6;  loss,  o°.8  =  1.15 
per  cent.  Manometer:  No.  6;  volume  of  air,  396.89;  displace- 
ment, 0.05  mm.  Cell  used,  D.  Resistance  of  membrane, 
220,000.  Corrections:  (i)  atmospheric  pressure,  0.99;  (2) 
liquids  in  manometer,  0.65;  (3)  dilution,  0.07;  (4)  concen- 
tration, o;  (5)  capillary  depression,  0.02.  Initial  pressure, 
.  Time  of  setting  up  cell,  4.00  P.M.,  Apr.  n,  1907. 

Temperature.  Pressure. 


Time. 

Solution.  Manometer. 

V  U1U11  1C 

air. 

Osmotic. 

Gas.    Difference. 

April  1  2. 

IO.OO  A.M. 

10° 

.0 

10° 

•4 

26 

.78 

H 

•39 

13 

•85 

0-54 

I.OO  P.M. 

9° 

.8 

10° 

5 

26 

.81 

H 

•37 

13 

.84 

0-53 

5.OO  P.M. 

9° 

7 

10°, 

4 

26 

79 

14 

39 

13 

83 

0.56 

14.38    13.84   0.54 

Loss  in  rotation  corrected  as  inversion. 
Molecular  osmotic  pressure,  23.97. 
Molecular  gas  pressure,  23.07. 
Ratio  of  osmotic  to  gas  pressure,  1.039. 


i6 

Table  XL 

0.7  Wt.  normal  solution.  Bxp.  No.  i.  Rotation:  (i) 
original,  79.3;  (2)  at  conclusion  of  Exp.,  78°. 3;  loss,  i°  =  i.26 
per  cent.  Manometer:  No.  21;  volume  of  air,  477.75;  dis- 
placement, o.i  i  mm.  Cell  used,  D.  Resistance  of  membrane, 
370,000.  Corrections:  (i)  atmospheric  pressure,  i.oo;  (2) 
liquids  in  manometer,  0.55;  (3)  dilution,  0.15;  (4)  concen- 
tration, o;  (5)  capillary  depression,  0.02.  Initial  pressure, 
13.92.  Time  of  setting  up  cell,  4.00  P.M.,  Apr.  25,  1907. 

Temperature.  Pressure. 


Time. 

Solution. 

Manometer. 

V  U1U  U1C 

air. 

Osmotic. 

Gas 

.    Difference. 

April  25. 

8.30  P.M. 

11°.  1 

\       12°. 

35 

27 

.19 

17 

.00 

16 

•23 

O. 

77 

April  26. 

2.00  P.M. 

II0.: 

>       12° 

25 

27 

•15 

17 

•03 

16 

•23 

O 

80 

April  27. 

11.00  A.M. 

11°.  i 

\       12° 

•4 

27 

•03 

17 

.04 

16 

.26 

O 

,78 

17.04     16.24    °-78 
Loss  in  rotation  corrected  as  inversion. 
Molecular  osmotic  pressure,  24.32. 
Molecular  gas  pressure,  23.20. 
Ratio  of  osmotic  to  gas  pressure,  1.048. 

Table  XII. 

i.o  Wt.  normal  solution.  Bxp.  No.  i.  Rotation:  (i) 
original,  107°. 6;  (2)  at  conclusion  of  Bxp.,  io6°.4;  loss,  i°.2  = 
1. 12  per  cent.  Manometer:  No.  13;  volume  of  air,  435.09; 
displacement,  0.03  mm.  Cell  used,  D.  Resistance  of  mem- 
brane, 220,000.  Corrections:  (i)  atmospheric  pressure,  i.oo; 
(2)  liquids  in  manometer,  0.66;  (3)  dilution,  0.19;  (4)  concen- 
tration, o;  (5)  capillary  depression,  0.02.  Initial  pressure, 
19.92.  Time  of  setting  up  cell,  4.00  P.M.,  May  i,  1907. 

Temperature.  Pressure. 


Time.  Solution.  Manometer.  air.  Osmotic.  Gas.     Difference. 
May  i. 

5.00P.M.  10°. 5     11°. 4  17.10  24.93  23.12     1.81 

May  2. 

11.30  A.M.  9°. 8       11°. 2  17.10  24.94  23.07       1.87 

9.00P.M.  9°. 4     10°.  65  17.16  24.86  23.03     1.83 


24.91    23.07    1.84 

Loss  in  rotation  corrected  as  inversion. 
Molecular  osmotic  pressure,  24.91. 
Molecular  gas  pressure,  23.07. 
Ratio  of  osmotic  to  gas  pressure,  1.080. 


•-2    oOP*coNwcoTt-Tj-Tj-'ri-r>. 

tJg    fOro^O    ON  ON  cs    »O  to  tOOO   C<    O 

'l"  "=ss2"8J? 

o    rj~  rj-  O   O   •"*   co  O  M  t^  O  t^  O 
"5    rj*  "^  OO    C<    N    iO  O    O    O    tO  M    M 

•sc  ^2222"^;? 

23  a 

o.. 

rh  t^  to 

•g        ~   -  ^^^MMW 

s 

^    o 

S 

^  S    ^"  ro  OO    *O  OO    t^**  O    0s*  O  OO 

'5    •^•'^"i^*-<    «    T^-ONOO    O   roO   ON 

*;   cs  cs  Tj-r>.^.ONt-i  M  ci  Tt-t^-Th 

s  r  L  £ 

K_v        C3 

^N       S 

•S     §  o 

•S      ?S         g.So    O    ON  O  O 
Q     C/)         "*-g    O    t^OO    ON  1000    M 

fclo    OOOOCOMMO^ 


5     a 


g    iO  iO  O    W    iO  lOOO    ON  ONOO    rj-  ON 
J'SOOOOOOOOOOOO 

•=    CNONO    O    ONONONONONONHH    ON 


a§ 
§|  „  H 


i8 


•j  I    O  cs   ^0  w   •<$•  rj-  ^  r^ 

£  V     COVO     ON  04    lOCQ    04     O 


<L>  P-   O4    -^-vO    ONM    covo    CO 

*«  M      M      M     04 


ll 


£ 


1    Tf-0 
!2   ^°o 


M     CO   CO    O     t^> 
O4    iO  O    'O  »H 


-•?     04     Th 


•3  g  lOcOcOt^ONOOOO    r}- 

,§5  ^^    C4    10  O    10  04    04 

nJ!  04   Tft^ON04   rht^io 

OTJ  M    M    M    04 


COOO    ^4     M 
ON  co  O    ON 


W      M      M      O4 


§ 

e     «•     a 

1     gfl| 

0 

0 
00 

t^OO 

CO  »0 

M  M 

vO    O4 
O4    M 

CO 
ON 

•O     •*-  8 

6 

O 

6  6 

M  M 

M      M 

6 

II 

•2      §    10  O    ON  10  ONOO    ^  ON 

&l^-r* 

oooooooo 


H      8          M 


19 

The  essential  data  of  the  individual  measurements  are 
given  in  Tables  I.  to  XII.,  inclusive,  and  are  summarized 
in  Table  XIII.  They  reappear  as  mean  values  for  each 
concentration  in  Table  XIV. 

The  wide  variation  in  temperature  as  compared  with  the 
next  series  will  be  seen  by  referring  to  Table  XIV.  Though 
the  average  temperature  for  the  series  was  10°,  it  will  be 
noticed  that  the  mean  temperatures  for  the  individual 
concentrations  varied  from  9°. 5  in  the  o.i  and  0.4  normal 
to  11°. 4  in  the  0.7  normal. 

That  little  dilution  could  have  taken  place  from  slipping 
of  the  manometers,  is  seen  in  Table  I.  to  XII.,  inclusive. 
The  largest  displacement  was  0.4  mm.  in  case  of  the  0.3 
normal,  while  the  average  displacement  was  only  0.12  mm. 

The  average  loss  in  rotation  given  in  Table  XIV.  was 
0.93  per  cent.  This  was  a  marked  improvement  on  the 
losses  in  previous  series  of  the  osmotic  pressures  of  cane 
sugar  solutions.  The  average  losses  in  rotation  in  the  three 
former  series  were  as  follows : 


Series. 

Temperature. 

I,oss,  per  cent. 

II. 

20° 

2.8    l 

III. 

0° 

i-472 

IV. 

4° 

I.  283 

This  series. 

10° 

•  93 

In  Tables  I.  to  XII.,  inclusive,  the  loss  in  rotation  was 
corrected  as  being  due  wholly  to  inversion.  Even  at  this 
time,  however,  such  correction  was  believed  to  give  too 
low  results.  Consequently,  the  results  were  also  corrected 
by  ascribing  one  half  the  loss  in  rotation  to  dilution.  The 
reason  for  such  correction  has  been  fully  explained  in  con- 
nection with  earlier  work.1  The  pressures,  as  corrected 
for  half  dilution,  are  given  in  Table  XIII.,  and  the  mean 
results  in  Table  XIV. 

The  pressures,  as  they  would  be  without  correction,  either 
for  inversion  or  for  dilution,  i.  e.,  the  actually  observed 

*  Am.  Chem.  J.,  36,  39. 
2  Ibid.,  37,  457. 

*  Ibid.,  38,  178. 

*  Ibid.,  37,  463. 


2O 

osmotic  pressures,  will  likewise  be  noticed  in  Tables  XIII. 
and  XIV.  These  two  columns  are  based  on  the  fact,  recently 
discovered,  that  practically  all  the  dilution  has  heretofore 
taken  place  while  the  cell  was  being  opened  and  is,  there- 
fore, subsequent  to  the  measurement  of  osmotic  pressure. 
It  is  evident  that  such  dilution  should  be  excluded  in  any 
correction  of  the  observed  pressures. 

The  experimental  proof  on  which  this  fact  is  based,  and 
which  is  of  such  a  nature  as  to  leave  little  doubt  that  the 
actually  observed  osmotic  pressure  is  an  extremely  close 
approximation  to  the  true  pressure,  will  be  given  in  the 
discussion  of  the  results  obtained  in  Series  II. 

Table  XV.  shows  the  differences  between  the  osmotic 
pressures  calculated  in  the  three  different  ways  just  men- 
tioned and  the  gas  pressures  for  the  corresponding  con- 
centrations and  temperatures. 

Table  XV. — Differences  between  Osmotic  and  Gas  Pressure. 
Series  I. 


Weight- 
normal 
concentra- 
tion. 

If  all  loss 
in  rotation 
is  ascribed 
to  inversion. 

If  one  half 
the  loss  in 
rotation 
is  ascribed 
to  dilution. 

If  all  loss  in 
rotation  is 
ascribed  to 
subsequent 
dilution. 

O.  I 
0.2 

o.  14 
o.  16 

0.15 
O.2I 

o.  14 
0.18 

0-3 

0.24 

0.30 

0.28 

0.4 

0.25 

0-35 

0.31 

0-5 
0.6 
0.7 
I  .0 

o  39 
0-54 
0.78 
1.84 

0-55 
0-74 
I  .04 
2.17 

0.49 

0.66 

o-93 
2.03 

In  Table  XVI.  are  given  the  ratios  of  the  molecular  osmotic 
pressures  to  the  molecular  gas  pressures  likewise  based  upon 
the  three  different  methods  of  correction. 


QFTHfe 

UNIVERSITY 


21 


Table  XVI. — Ratios  of  Molecular  Osmotic  to  Molecular  Gas 

Pressure. 

Series  I. 


Weight- 
normal 
concentra- 
tion. 

If  all  loss 
in  rotation 
is  ascribed 
to  inversion. 

O.  I 

1-057 

0.2 

1-035 

o-3 

1-035 

o-4 

I.O27 

o-5 
0.6 

0.7 

I.O 

1-034 
1.039 
1.048 
I.OSO 

If  one  half 
the  loss  in 
rotation  is 
ascribed  to 
dilution. 

If  all  loss 
in  rotation 
is  ascribed  to 
subsequent 
dilution. 

I  .O6l 

•059 

•045 

.040 

•045 
-038 

.040 
•033 

049 
•053 
.069 
.094 

„ 

.042 
.046 

t-059 
[.087 

A  minimum  in  the  ratios  will  be  noticed  in  the  0.4  normal. 
A  similar  minimum  was  observed  in  the  case  of  the  0.4 
normal1  at  o°,  but  at  4°  the  minimum  appeared  to  occur 
in  the  0.3  normal.2 

SERIES  II. 

Effective  methods  having  been  devised  for  overcoming 
the  dilution  in  the  cell  and  for  greatly  reducing  the  "ther- 
mometer effects,"  it  seemed  desirable  to  redetermine  the 
osmotic  pressure  of  cane  sugar  solutions  at  10°.  The  results 
of  such  a  redetermination  are  given  in  the  following  tables. 

During  the  entire  two  months  over  which  this  series  of 
measurements  extended,  the  maximum  fluctuation  in  the 
temperature  of  the  bath  was  only  o°.4.  The  fluctuation 
in  consecutive  readings,  however,  which  is  the  thing  to  be 
guarded  against,  in  only  two  cases  was  as  high  as  o°.2, 
while  the  average  fluctuation  in  temperature  was  less  than 
o°.i.  Consequently,  temperature  effects  were  practically 
eliminated  in  Series  II. 

The  average  displacement  of  the  manometers  was  0.3 
mm.  This  displacement  was  too  small  to  cause  any  sensible 
dilution  and,  consequently,  any  loss  in  rotation. 

The  third,   and  chief  cause  of  uncertainty  regarding  the 

*  Am.  Chem.  J.,  38,  207. 
8,  207. 


22 

correct  osmotic  pressures,  was  satisfactorily  solved  by  the 
use  of  the  hypodermic  needle  in  opening  the  cell. 

The  manometers  used  in  this  series  were  filled  with  nitro- 
gen instead  of  air.  It  had  been  found  in  the  course  of  earlier 
work  that  in  manometers  filled  with  air  there  is  a  slow  and 
continuous  diminution  in  the  volume  of  the  gas,  notwith- 
standing the  extreme  care  with  which  the  mercury  had 
been  prepared. 

This  loss  may  be  due  to  two  causes — either  to  the  action 
of  the  oxygen  of  the  air  on  the  mercury  itself  or  on  any  traces 
of  amalgam  present,  or  to  the  stretching  of  the  manometer 
tube  under  pressure.  The  question  of  this  stretching  under 
pressure  is  now  under  investigation  in  this  laboratory. 

The  solutions  were,  of  course,  made  up  on  the  weight- 
normal  basis  and  the  sugar  used  was  the  purest  obtainable 
rock  candy.  Two  analyses  made  in  this  laboratory  gave 

Carbon. 


Found,  Theoretical, 

per  cent.  per  cent. 

I 42  .02  42  .08 

2 42  .  08 

Hydrogen. 

Found,  Theoretical, 

per  cent.  per  cent. 

i 6 . 42  6 . 48 

2 6.47 

Tables  I.  to  XX.,  inclusive,  present  the  essential  data 
of  the  individual  determinations.  These  are  summarized 
in  Table  XXI.  Table  XXII.  contains  the  mean  values 
for  each  concentration  of  solution. 


23 

Table  I. 

o.i  Wt.  normal  solution.  Experiment  No.  i.  Rotation:  (i) 
original,  12°. 8;  (2)  at  conclusion  of  Exp.,  12°. 8;  loss,  o°. 
Manometer:  No.  13;  volume  of  nitrogen,  432.84;  displacement, 
0.08  mm.  Cell  used,  H.  Resistance  of  membrane,  136,000. 
Corrections:  (i)  atmospheric  pressure,  i.oo;  (2)  liquids  in 
manometer,  0.46;  (3)  dilution,  o;  (4)  concentration,  o;  (5) 
capillary  depression,  0.02.  Initial  pressure,  1.97.  Time  of 
setting  up  cell,  4.00  P.M.,  March  2,  1908. 

Temperature.                                             Pressure. 
< « »  Volume   . • » 


Time.  Solution.    Manometer.        N2.        Osmotic.     Gas.    Difference. 

March  5. 

11.45  P.M.      10°. o     io°.9     147.12     2.42     2.31     o.n 

March  6. 
IO.3O  A.  M.        IO°.O       10°.  7       146.78      2.43       2.31       O.I2 

2.43       2.31       0.12 

Molecular  osmotic  pressure,  24.25. 

Molecular  gas  pressure,  23 . 10. 

Ratio  of  osmotic  to  gas  pressure,  i  .050. 


Table  II. 

o.i  Wt.  normal  solution.  Experiment  No.  2.  Rotation:  (i) 
original,  12°. 8;  (2)  at  conclusion  of  Exp.,  12°. 8;  loss, 
o°.  Manometer:  No.  6;  volume  of  nitrogen,  405.34;  displace- 
ment, 0.09  mm.  Cell  used,  G.  Resistance  of  membrane, 
219,000.  Corrections:  (i)  atmospheric  pressure,  i.oo;  (2) 
liquids  in  manometer,  0.45;  (3)  dilution,  o;  (4)  concentra- 
tion, o;  (5)  capillary  depression,  0.02.  Initial  pressure,  2.69. 
Time  of  setting  up  cell,  3.30  P.M.,  March  2,  1908. 


Temperature. 

Pressure. 

Time.            Solution. 

Manometer.       Nj.       Osmotic. 

Gas.    Difference. 

March  5. 

8.40  A.M. 

10°.  C 

)       10°. 

3 

136 

.68 

2 

•43 

2 

•31 

0. 

12 

II  .15  P.M. 

10°.  C 

)       10°. 

9 

136 

•17 

2 

•45 

2 

•31 

O. 

14 

March  6. 

10.30  A.M. 

10°.  C 

)       10°. 

7 

136 

.28 

2 

•44 

2 

•31 

O. 

13 

2 

•44 

2 

•31 

0. 

13 

Molecular  osmotic  pressure,  24 . 40. 

Molecular  gas  pressure,  23 . 10. 

Ratio  of  osmotic  to  gas  pressure,  i .  056. 


24 

Table  III. 

o. 2  Wt.  normal  solution.  Experiment  No.  i.  Rotation:  (i) 
original,  25°.o;  (2)  at  conclusion  of  Exp.,  25°.o;  loss, 
o°.  Manometer:  No.  13;  volume  of  nitrogen,  432.84;  displace- 
ment, 0.09  mm.  Cell  used,  G.  Resistance  of  membrane, 
283,000.  Corrections:  (i)  atmospheric  pressure,  i.oo;  (2) 
liquids  in  manometer,  0.56;  (3)  dilution,  o;  (4)  concentra- 
tion, o;  (5)  capillary  depression,  0.02  Initial  pressure,  4.66. 
Time  of  setting  up  cell,  11.30  A.M.,  January  21,  1908. 

Temperature.  Pressure. 

Volume 


Time.  Solution.  Manometer.        N2.  Osmotic.    Gas.    Difference. 
Jan.  22. 

H.4OA.M.  io°.2     io°.8     82.91  4.80    4.62     0.18 

8.10  P.M.  10°. o     10°. 9     82.87  4-8o    4-62     o-18 

Jan.  23. 

10.00  A. M.  10°. O       10°. 7      82.37  4.83      4.62      0.21 


4.81      4.62      O.I9 

Molecular  osmotic  pressure,  24.05. 

Molecular  gas  pressure,  23.10. 

Ratio  of  osmotic  to  gas  pressure,  1.041. 


Table  IV. 

0.2  Wt.  normal  solution.  Experiment  No.  2.  Rotation:  (i) 
original,  25°.o;  (2)  at  conclusion  of  Exp.,  25°.o;  loss, 
o°.  Manometer:  No.  6;  volume  of  nitrogen,  405.34;  displace- 
ment, 0.14  mm.  Cell  used,  D.  Resistance  of  membrane, 
141,000.  Corrections:  (i)  atmospheric  pressure,  i.oo;  (2) 
liquids  in  manometer,  0.54;  (3)  dilution,  o;  (4)  concentra- 
tion, o;  (5)  capillary  depression,  0.02.  Initial  pressure,  4.78. 
Time  of  setting  up  cell,  11.30  A.M.,  January  21,  1908. 

Temperature.  Pressure. 


Time. 

Solution.  Manometer.        N2. 

Osmotic 

.    Gas.    Difference. 

Jan. 

22. 

II.4O 

A.M. 

10°.  2 

10° 

.8 

76.98 

4 

.82 

4 

.62 

o. 

20 

8.10 

P.M. 

10°.  0 

10° 

•9 

76.98 

4 

.82 

4 

.62 

o. 

20 

10.30 

P.M. 

10°.  0 

10° 

.8 

76.84 

4 

•83 

4 

.62 

0. 

21 

Jan. 

23. 

IO.OO 

A.M. 

10°.  0 

10° 

•7 

76.62 

4 

•85 

4 

.62 

o. 

23 

4.83      4.62       0.21 

Molecular  osmotic  pressure,  24.15. 

Molecular  gas  pressure,  23.10. 

Ratio  of  osmotic  to  gas  pressure,  1.045. 


25 

Table  V. 

0.3  Wt.  normal  solution.  Experiment  No.  i.  Rotation:  (i) 
original,  36°.6;  (2)  at  conclusion  of  Exp.,  36°.6;  loss, 
o°.  Manometer:  No.  6;  volume  of  nitrogen,  405. 34;  displace- 
ment, 0.02  mm.  Cell  used,  G.  Resistance  of  membrane, 
158,000.  Corrections:  (i)  atmospheric  pressure,  0.99;  (2) 
liquids  in  manometer,  0.58;  (3)  dilution,  o;  (4)  concentra- 
tion, o;  (5)  capillary  depression,  0.02.  Initial  pressure,  5.00. 
Time  of  setting  up  cell,  5.00  P.M.,  March  12,  1908. 

Temperature.  Pressure. 

Volume 


Time.  Solution.  Manometer.        Nj.        Osmotic.    Gas.    Difference. 

March  13. 

10.30  P.M.        io°.o     io°.6     53.40     7.20     6.92     0.28 

March  14. 

8.45P.M.        10°. o     10°. 7     53.16     7.24     6.92     0.32 

March  15. 
10.00  A.M.  10°. O       10°. 8       53-44      7-21       6.92       0.29 


7-22       6.92      0.30 

Molecular  osmotic  pressure,  24.07. 

Molecular  gas  pressure,  23.07. 

Ratio  of  osmotic  to  gas  pressure,  1.043. 

Table  VI. 

0.3  Wt.  normal  solution.  Experiment  No.  2.  Rotation:  (i) 
original,  36°.7;  (2)  at  conclusion  of  Exp.,  36°.7;  loss, 
o°.  Manometer:  No.  6;  volume  of  nitrogen,  405.34;  displace- 
ment, 0.08  mm.  Cell  used,  O.  Resistance  of  membrane, 
112,000.  Corrections:  (i)  atmospheric  pressure,  0.99;  (2) 
liquids  in  manometer,  0.58;  (3)  dilution,  o;  (4)  concentra- 
tion, o;  (5)  capillary  depression,  0.02.  Initial  pressure,  5.36. 
Time  of  setting  up  cell,  4.00  P.M.,  March  17,  1908. 

Temperature.  Pressure. 

Volume 


Time.  Solution.  Manometer.        Ng.  Osmotic.    Gas.  Difference. 
March  19. 

5.00P.M.  10°. o  10°. 9  53-79  7-l5  6.92  0-23 

IO.OO  P.M.  10°.  I  IO°.9  53-86  7.14  6.93  0. 2 1 
March  20. 

8.30A.M.  10°. i  10°. 6  53.65  7.17  6.93  0.24 

10.30  P.M.  10°. o  10°. 8  53.73  7.15  6.92  0.23 


7-15       6.93      0.22 

Molecular  osmotic  pressure,   23.83. 

Molecular  gas  pressure,  23.08. 

Ratio  of  osmotic  to  gas  pressure,  1.032. 


26 

Table  VII. 

0.4  Wt.  normal  solution.  Experiment  No.  i.  Rotation:  (i) 
original,  48°.!;  (2)  at  conclusion  of  Exp.,  48°.!;  loss, 
o°.  Manometer:  No.  6;  volume  of  nitrogen,  405.34;  displace- 
ment, o.o  mm.  Cell  used,  H.  Resistance  of  membrane, 
183,000.  Corrections:  (i)  atmospheric  pressure,  0.99;  (2) 
liquids  in  manometer,  0.59;  (3)  dilution,  o;  (4)  concentra- 
tion, o;  (5)  capillary  depression,  0.02.  Initial  pressure,  8.61. 
Time  of  setting  up  cell,  4.00  P.M.,  February  24,  1908. 

Temperature.  Pressure. 


Time. 

Solution.  Manometer 

-»    voiumc 

N2. 

Osmotic 

.    Gas.    Difference. 

Feb. 

25. 

8.00 

P.M. 

10°.  I 

11°.  2 

40 

.86 

9 

53 

9- 

24 

0. 

29 

Feb. 

26. 

8.00 

P.M. 

10°.  I 

10°.  6 

40 

.98 

Q 

•52 

9- 

24 

0, 

28 

IO.OO 

P.M. 

10°.  0 

10°.  9 

40 

•85 

9 

•54 

9- 

23 

o 

31 

9.53   9.24   0.29 

Molecular  osmotic  pressure,  23.83. 

Molecular  gas  pressure,  23.10. 

Ratio  of  osmotic  to  gas  pressure,  1.031. 

Table  VIII. 

0.4  Wt.  normal  solution.  Experiment  No.  2.  Rotation:  (i) 
original,  48°.!;  (2)  at  conclusion  of  Exp.,  48°.!;  loss, 
o°.  Manometer:  No.  13;  volume  of  nitrogen,  432.84;  displace- 
ment, 0.14  mm.  Cell  used,  D.  Resistance  of  membrane, 
220,000.  Corrections:  (i)  atmospheric  pressure,  i.oi;  (2) 
liquids  in  manometer,  0.60;  (3)  dilution,  o;  (4)  concentra- 
tion, o;  (5)  capillary  depression,  0.02.  Initial  pressure,  7.55. 
Time  of  setting  up  cell,  4.30  P.M.,  February  24,  1908. 

Temperature.  Pressure. 

Volume 


Time.  Solution.  Manometer.        Nj.        Osmotic.    Gas.     Difference. 

Feb.  25. 

8.30A.M.      10°.  i       ioo°-75  43.17     9.64     9.24     0.40 

2.00P.M.         10°.  I          100°.  9      43-37       9-59      9.24      0.35 

5.00P.M.      10°. 05     110°. o     43-34     9-6i     9-23     0.38 

Feb.  26. 

10.00  P.M.      10°. o       100°. 9     43.38     9.61     9.23    0.38 

9.6l       9.24      0.38 

Molecular  osmotic  pressure,  24.03. 

Molecular  gas  pressure,  23.10. 

Ratio  of  osmotic  to  gas  pressure,   1.040. 


27 

Table  IX. 

0.5  Wt.  normal  solution.  Experiment  No.  i.  Rotation:  (i) 
original,  59°.o;  (2)  at  conclusion  of  Kxp.,  59°.o;  loss, 
o°.  Manometer:  No.  13;  volume  of  nitrogen,  432.84;  displace- 
ment, 0.03  mm.  Cell  used,  D.  Resistance  of  membrane, 
220,000.  Corrections:  (i)  atmospheric  pressure,  i.oo;  (2) 
liquids  in  manometer,  0.61;  (3)  dilution,  o;  (4)  concentra- 
tion, o;  (5)  capillary  depression,  0.02.  Initial  pressure,  7.9. 
Time  of  setting  up  cell,  3.30  P.M.,  February  20,  1908. 

Temperature.  Pressure. 


Time. 

Solution.  Manometer.        N2- 

Osmotic. 

Gas.      Difference. 

Feb.  21. 

9.00  A.M. 

10°. 

0 

10° 

.6 

35 

•13 

II 

•95 

II 

•54 

0.41 

5.OO  P.M. 

10°. 

0 

11° 

.0 

35 

.  ii 

II 

.96 

II 

•54 

0.42 

Feb.  22. 

9.00  A.M. 

10°. 

0 

10° 

•4 

35 

•15 

II 

•94 

II 

•54 

0.40 

4.OO  P.M. 

9°- 

9 

10° 

.8 

35 

.04 

II 

•98 

II 

•54 

0.44 

11.96     11.54    0.42 
Molecular  osmotic  pressure,  23.92. 
Molecular  gas  pressure,  23.08. 
Ratio  of  osmotic  to  gas  pressure,  1.036. 

Table  X. 

0.5  Wt.  normal  solution.  Experiment  No.  2.  Rotation:  (i) 
original,  58°.7;  (2)  at  conclusion  of  Exp.,  58°.6;  loss, 
o°.  i  =  o.  1 7  per  cent.  Manometer:  No.  13 ;  volume  of  nitrogen, 
432.84;  displacement,  0.64  mm.  Cell  used,  G.  Resistance  of 
membrane,  139,000.  Corrections:  (i)  atmospheric  pressure, 
0-995  (2)  liquids  in  manometer,  0.61;  (3)  dilution,  o.oi;  (4) 
concentration,  o;  (5)  capillary  depression,  0.02.  Initial  pres- 
sure, 3.88.  Time  of  setting  up  cell,  4.00  P.M.,  March  17,  1908. 

Temperature.  Pressure. 


Time. 

Solution.  Manometer.         N2. 

Osmotic. 

Gas.     Difference. 

March  18. 

IO.OO  P.M. 

10° 

.0 

10°. 

9 

35-oo 

12 

.00 

II 

•54 

0 

.46 

March  19. 

8.00  P.M. 

10° 

.0 

10° 

.8 

34-87 

12 

.04 

II 

•54 

0 

•  50 

March  20. 

IO.30  A.M. 

10° 

.0 

10° 

.8 

34.89 

12 

.04 

II 

•54 

0 

•  50 

12.03    11.54    0.49 
Loss  in  rotation  corrected  as  inversion. 
Moleculai  osmotic  pressure,  24.01. 
Molecular  gas  pressure,  23.09. 
Ratio  of  osmotic  to  gas  pressure,  1.042. 


28 

Table  XL 

0.6  Wt.  normal  solution.  Experiment  No.  i.  Rotation:  (i) 
original,  69°.2;  (2)  at  conclusion  of  Exp.,  69°.2.  loss, 
o°.  Manometer:  No.  13;  volume  of  nitrogen,  432.84;  displace- 
ment, 0.06  mm.  Cell  used,  D.  Resistance  of  membrane, 
185,000.  Corrections:  (i)  atmospheric  pressure,  i.oo;  (2) 
liquids  in  manometer,  0.62;  (3)  dilution,  o;  (4)  concentra- 
tion, o;  (5)  capillary  depression,  0.02.  Initial  pressure,  9.57. 
Time  of  setting  up  cell,  5.00  P.M.,  February  17,  1908. 

Temperature.                                               Pressure. 
. • >    Volume     < • > 


Time.  Solution.  Manometer.        N2.  Osmotic.  Gas.    Difference. 
Feb.  18. 

9.00A.M.          10°.  i     10°. 4     29.10  14.50  13.85     0.65 

5.00  P.M.          io°.i     10°. 8     29.02  14.55  13.85     0.70 

Feb.  19. 

2.00P.M.          io°.i     io°.4     29.11  14.53  J3-85     0.68 


14.53     13.85     0.68 
Molecular  osmotic  pressure,  24.22. 
Molecular  gas  pressure,   23.09. 
Ratio  of  osmotic  to  gas  pressure,  1.049. 

Table  XII. 

o. 6  Wt.  normal  solution.  Experiment  No.  2.  Rotation:  (i) 
original,  69°.2j  (2)  at  conclusion  of  Exp.,  69°.2;  loss, 
o°.  Manometer:  No.  6;  volume  of  nitrogen,  405.34;  displace- 
ment, 0.03  mm.  Cell  used,  G.  Resistance  of  membrane, 
278,000.  Corrections:  (i)  atmospheric  pressure,  i.oo;  (2) 
liquids  in  manometer,  0.61 ;  (3)  dilution,  o;  (4)  concentra- 
tion, o;  (5)  capillary  depression,  0.02.  Initial  pressure,  9.8. 
Time  of  setting  up  cell,  5.00  P.M.,  February  17,  1908. 

Temperature.  Pressure. 

Volume 


Time.  Solution.  Manometer.        Nj.  Osmotic.     Gas.     Difference. 

Feb.  18. 

9.00A.M.          io°.i     io°.4     27.19     14.53     13.85     0.68 
5.00  P.M.          10°. i     10°. 8     27.11     14.57     13.85     0.72 

Feb.  19. 

9.00A.M.          10°. i     10°. 5     27.20     14.53     13.85     0.68 

2.00P.M.  10°. I       10°. 4       27.17       14.57       13.85      0.72 

14.55    13.85   0.70 

Molecular  osmotic  pressure,  24.25. 

Molecular  gas  pressure,  23.09. 

Ratio  of  osmotic  to  gas  pressure,  1.051. 


29 

Table  XIII. 

0.7  Wt.  normal  solution.  Experiment  No.  i.  Rotation: 
(i)  original,  79°.3;  (2)  at  conclusion  of  Exp.,  79°.2j  loss, 
o °.  i  =  0.13  per  cent.  Manometer:  No.  6;  volume  of  nitro- 
gen, 405. 34;  displacement,  0.16  mm.  Cell  used,  G.  Resistance 
of  membrane,  373,000.  Corrections:  (i)  atmospheric  pressure, 
0.99;  (2)  liquids  in  manometer,  0.61;  (3)  dilution,  o.oi ;  (4) 
concentration,  o;  (5)  capillary  depression,  0.02.  Initial  pres- 
sure, 11.38.  Time  of  setting  up  cell,  4.00  P.M.,  January  24, 
1908. 

Temperature.  Pressure. 


Time. 

Solution.  Manometer.        Nj. 

Osmotic.    Gas.    Difference. 

Jan.  25. 

11.00  A.M. 

10° 

.  I 

10°. 

4 

23 

19 

17 

.  IO 

16. 

16 

0.94 

2.OO  P.M. 

10° 

.0 

10°. 

IJ 

23 

.18 

17 

.  II 

16, 

16 

0-95 

5.00  P.M. 

10° 

.0 

10°. 

8 

23 

23 

17 

.07 

16, 

16 

0.91 

17.09     16.16     0.93 
Loss  in  rotation  corrected  as  inversion. 
Molecular  osmotic  pressure,  24.41. 
Molecular  gas  pressure,  23.09. 
Ratio  of  osmotic  to  gas  pressure,   1.058. 

Table  XIV. 

0.7  Wt.  normal  solution.  Experiment  No  2.  Rotation: 
(i)  original,  79°.3;  (2)  at  conclusion  of  Exp.,  79°-3;  loss, 
o°.  Manometer:  No.  13;  volume  of  nitrogen,  432.84;  displace- 
ment, 0.17  mm.  Cell  used,  D.  Resistance  of  membrane, 
187,000.  Corrections:  (i)  atmospheric  pressure,  0.99;  (2) 
liquids  in  manometer,  0.63;  (3)  dilution,  o;  (4)  concentra- 
tion, o;  (5)  capillary  depression,  0.02.  Initial  pressure,  10.93. 
Time  of  setting  up  cell,  4.00  P.M.,  January  24,  1908. 


Temperature. 

i 

Pressure. 

Time. 

Solution.  Manometer.        N2. 

Osmotic. 

Gas.    Difference. 

Jan.  25. 

II.OO  A.M. 

10° 

.  I 

10° 

4 

24 

.85 

17 

.07 

16. 

16 

0.91 

2.00  P.M. 

10° 

.0 

10° 

7 

24 

.84 

17 

.08 

16. 

16 

0.92 

5.OO  P.M. 

10° 

.0 

10° 

.8 

24 

.82 

17 

.  IO 

16. 

16 

0.94 

17.08     16.16     0.92 
Molecular  osmotic  pressure,  24.40. 
Molecular  gas  pressure,   23.09. 
Ratio  of  osmotic  to  gas  pressure,   1.057. 


30 

Table  XV. 

0.8  Wt.  normal  solution.  Experiment  No.  i.  Rotation: 
(i)  original,  89°.!;  (2)  at  conclusion  of  Exp.,  88°.9;  loss, 
o°.2  =  0.22  per  cent.  Manometer:  No.  6;  volume  of  nitrogen, 
405*34 ;  displacement,  0.28  mm.  Cell  used,  G.  Resistance  of 
membrane,  186,000.  Corrections:  (i)  atmospheric  pressure, 
i.oi;  (2)  liquids  in  manometer,  0.625(3)  dilution,  0.03;  (4) 
concentration,  o;  (5)  capillary  depression,  0.02.  Initial  pres- 
sure, 8.96.  Time  of  setting  up  cell,  5.00  P.M.,  January  29,  1908. 

Temperature.  Pressure. 


Time. 

Solution.  Manometer.        Ng. 

Osmotic. 

Gas.    Difference. 

Jan.  30. 

9.0O 

P.M. 

9° 

9 

10°. 

8 

20. 

17 

19 

,70 

18.46 

1.24 

Jan.  31. 

2.0O 

P.M. 

10°. 

0 

10°. 

6 

20. 

14 

19 

73 

18.47 

1.26 

4-OO 

P.M. 

10°, 

o 

10°. 

7 

2O. 

19 

19 

68 

I8.47 

I.  21 

19.70    18.47    1-23 

Loss  in  rotation  corrected  as  inversion. 
Molecular  osmotic  pressure,   24.63. 
Molecular  gas  pressure,   23.09. 
Ratio  of  osmotic  to  gas  pressure,  1.067. 

Table  XVI. 

0.8  Wt.  normal  solution.  Experiment  No.  2.  Rotation: 
(i)  original,  89°. i;  at  conclusion  of  Exp.,  H9°.o;  loss, 
o°.i  =0.11  per  cent.  Manometer:  No.  13;  volume  of  nitro- 
gen, 432.84;  displacement,  0.25  mm.  Cell  used,  D.  Resistance 
of  membrane,  184,000.  Corrections:  (i)  atmospheric  pres- 
sure, i.oi;  (2)  liquids  in  manometer,  0.64;  (3)  dilution,  0.02; 
(4)  concentration,  o;  (5)  capillary  depression,  0.02.  Initial 
pressure,  8.46.  Time  of  setting  up  cell,  5.00  P.M.,  January 
29,  1908. 


Temperature. 

•»T«1...~._ 

Pressure. 

Time. 

Solution. 

Manometer.        Nj. 

Osmotic, 

,    Gas.    Difference. 

Jan.  30. 

2.0O  P.M. 

10°. 

0 

10°. 

6 

21 

•49 

19 

•77 

18 

•47 

1.30 

Jan.  31. 

2.OO  P.M. 

10°. 

0 

10°. 

6 

21 

•52 

19 

74 

18 

47 

1.27 

4.00  P.M. 

10°. 

0 

10°. 

7 

21 

•52 

19 

75 

18. 

47 

1.28 

19.75    18.47    1-28 

Loss  in  rotation  corrected  as  inversion. 
Molecular  osmotic  pressure,  24.69. 
Molecular  gas  pressure,  23.09. 
Ratio  of  osmotic  to  gas  pressure,  1.069. 


Table  XVII. 

0.9  Wt.  normal  solution.  Experiment  No.  i.  Rotation: 
(i)  original,  98°.4;  (2)  at  conclusion  of  Exp.,  98°.o;  loss, 
o°.4  =  0.41  percent.  Manometer:  No.  6;  volume  of  nitro- 
gen, 405. 34;  displacement,  0.88  mm.  Cell  used,  D.  Resistance 
of  membrane,  139,000.  Corrections:  (i)  atmospheric  pressure, 
0.98;  (2)  liquids  in  manometer,  0.621(3)  dilution,  0.06;  (4) 
concentration,  o ;  (5)  capillary  depression,  0.02.  Initial  pres- 
sure, 10.94.  Time  of  setting  up  cell,  4.00  P.M.,  February  14, 
1908. 

Temperature.  Pressure. 

Volume 


Time.  Solution.  Manometer.        N2.  Osmotic.    Gas.    Difference. 

Feb.  15. 

i. oo  P.M.      10°. o     11°. 4     17.91  22.24     20.77     1.47 

11.00  P.M.      IO°.0       10°. 6       17.93  22.22       20.77       1.45 

Feb.  16. 

10.00  A.M.      10°. O       IO°.4       17.93  22.2O       20-77       1.43 


22.22       20-77       1.45 

Loss  in  rotation  corrected  as  inversion. 
Molecular  osmotic  pressure,   24.69. 
Molecular  gas  pressure,  23.08. 
Ratio  of  osmotic  to  gas  pressure,  1.070. 

Table  XVIII. 

0.9  Wt.  normal  solution.  Experiment  No.  2.  Rotation: 
(i)  original,  98°. 4;  (2)  at  conclusion  of  Exp.,  98°.o;  loss, 
o°.4  —  0.41  per  cent.  Manometer:  No.  13 ;  volume  of  nitrogen, 
432.84;  displacement,  0.68  mm.  Cell  used,  G.  Resistance  of 
membrane,  278,000.  Corrections:  (i)  atmospheric  pressure, 
0.98;  (2)  liquids  in  manometer,  0.64;  (3)  dilution,  0.06;  (4) 
concentration,  o ;  (5)  capillary  depression,  0.02.  Initial  pres- 
sure, 8.33.  Time  of  setting  up  cell,  4.00  P.M.,  February  14, 
1908. 

Temperature.  Pressure. 


Time. 
Feb.  15. 

Solution.  Manometer.        N2.          Osmotic 

.    Gas.    Difference. 

11.30  P 
Feb.  16. 

.M. 

10° 

.0 

10°.  6 

I9.l8       22 

.22 

20.77 

i 

•45 

10.00 

A 

.M. 

10° 

,0 

10°.  4 

IQ.  1.5       22 

21 

20.77 

i 

.44 

22.22       20-77       r-45 

Loss  in  rotation  corrected  as  inversion. 
Molecular  osmotic  pressure,  24.69. 
Molecular  gas  pressure,  23.08. 
Ratio  of  osmotic  to  gas  pressure,  1.070. 


32 

Table  XIX. 

i.o  Wt.  normal  solution.  Experiment  No.  i.  Rotation; 
(i)  original,  io7°.4;  (2)  at  conclusion  of  Exp.,  io6°.8;  loss, 
o°.6  =  0.56  percent.  Manometer:  No.  13;  volume  of  nitro- 
gen, 432. 84;  displacement,  1.29  mm.  Cell  used,  D.  Resistance 
of  membrane,  139,000.  Corrections:  (i)  atmospheric  pressure, 
i.oi;  (2)  liquids  in  manometer,  0.64;  (3)  dilution,  0.09;  (4) 
concentration,  o;  (5)  capillary  depression,  0.02.  Initial  pres- 
sure, 8.89.  Time  of  setting  up  cell,  5.00  P.M.,  February  1 1,  1908. 

Temperature.  Pressure. 


Time. 

i  —  1     VU1UI11C 

Solution.  Manometer.       N2. 

Osmotic. 

Gas.    Difference. 

Feb.  12. 

8.00  P.M. 

10° 

•3 

11° 

.6 

17 

,04 

24 

•95 

23 

.  II 

1.84 

Feb.  13. 

9.00  A.M. 
2.00  P.M. 

10° 
10° 

.2 
.0 

10° 
10° 

•5 
•9 

17 
17 

00 

03 

25 
24 

•03 
.98 

23 
23 

.  10 
.08 

i-93 
1.90 

24.99    23.10    1.89 
Loss  in  rotation  corrected  as  inversion. 
Molecular  osmotic  pressure,  24.99. 
Molecular  gas  pressure,  23.10. 
Ratio  of  osmotic  to  gas  pressure,  1.081. 

Table  XX. 

i.o  Wt.  normal  solution.  Experiment  No.  2.  Rotation: 
(i)  original,  io7°.4;  (2)  at  conclusion  of  Exp.,  io6°.8;  loss, 
o°.6  =  0.56  percent.  Manometer:  No.  8;  volume  of  nitrogen, 
473.36;  displacement,  0.85  mm.  Cell  used,  G.  Resistance  of 
membrane,  278,000.  Corrections:  (i)  atmospheric  pressure, 
i.oi;  (2)  liquids  in  manometer,  0.66;  (3)  dilution,  0.09;  (4) 
concentration,  o;  (5)  capillary  depression,  0.02.  Initial  pres- 
sure, 10.24.  Time  of  setting  up  cell,  5.00  P.M.,  February  n, 
1908. 

Temperature.  Pressure. 


Time. 

Solution.  Manometer.        N2- 

Osmotic. 

Gas.    Difference. 

Feb.  12. 

11.30  P.M. 

10°.  2 

10°.  4 

18.67 

24.94 

23.10 

1.84 

Feb.  13. 

9.OO  A.M. 

10°.  2 

10°.  5 

18.66 

24-95 

23.10 

1.85 

2.0O  P.M. 

10°.  0 

10°.  9 

18.68 

24.92 

23.08 

1.84 

24.94    23.09    1.85 

Loss  in  rotation  corrected  as  inversion. 
Molecular  osmotic  pressure,  24.94. 
Molecular  gas  pressure,  23.09. 
Ratio  of  osmotic  to  gas  pressure,  1.080. 


33 


5|.«-.;w-^^4^:;i-«^^*w?" 

JjS    cocovo^O   ON  ON  CM   CM   10  tooo  oo   M   «   TJ-  TJ-  r»  t^  M   o 

£3  MMMMt-ll-HMMCMCMCMCM 

is 

tfi-S     CO  Tf"  M    CO  CM    lO  CO  w  vO     ^"  CO  *O  O  OO    CO  t~>>  OO  OO  OO    CO 

>£  '       '  ... 

O  MWMMhHMMMC^CSC^C^ 

fc" 
fi 

.     ,    M    COCM    «OCOMV£)    lOrOiOMQO    lOOO    CO  cOvO    M 
p,     •jg  g     rj-  rt-oO  OO    CM    M    lOvQ    ON  O    »O  10  M    O    " 

o      S.6 

a   c>c 

^     *2    O 

.§    "1 

^       ^>  .2     CO  T}~  M    CO  CM    10  CO  M  ^o    rO  CO  *O  ON  OO    O    *O  CM 

(/-)     C^  *     ^h  ^OO  OO    CM    M    iO\O    ONQ^OLOO    Ot^»t^CM    CM    ON 


I     g'.sl 

r  x-v  CJ  to  *i 


5      e 

«     oOOOOO»-4MM 


Qi-tMOOOOOOCMM 


oooooooooooooooooooo 

OOOOOOOOOOOOOOOOOOOO 


MCMHCMMCMMCMMCMMCMMCMMCMMCMMCM 


a 


O  rt 


*3     M    MCM    CM    COcOrJ-rJ-io 


r^oo  oo 


O   O 


^tjOOOOOOOOOOOOOOOOOOwM 


34 


'il*   M  ^  co  ^*  ^"  »o  o  t^-r^ON 

£  t>    CO  ^O    ON  OJ    ^O  OO    ^    ^^  t"^  O 

i  ..    C4    ^t"  vO    ON  M    co  vO  OO    O    CO 

£$                                            t-tMMMCNCS 

c" 

.2  d    rt-cs    ONt^O    •^•ONiOOO'O 
S2.2    -^-oo   M   100  ioO  t^-cs   O 
<utj      
**  «^    CS    ^h  !"*•  ON  d    rt~  t-»  ON  cs    >O 

^^                                               M      M      M      l-l      CN      N 

1 

<o    2 

"c3  ?     rj*  CX    ON  r»  M    rt*  O    t*»  CO  ^" 

i  .2    ^-  oo  w  to  O  *o  M  (•>•  co  M 

*§     ° 

0.73     CM    rj-t^ONCS     •ri-t^ONCS    to 

O*O                                            M     M     M      M      CS     CM 

g  1 

^ 

§  ° 

^ 

* 

•S» 

a* 

^ 

42 

•1    ^w  ^^S  ^^^^^ 
™    ^oo   M   to  O  to  O  r*»  CM   ON 

^ 

£     CM    4t^ONCM    -^IxONCM    ^*- 

<» 

,q                       M  M  M  M  CM  CM 

1  —  1 

fcj 

X 

*£» 

X 

?s 

u 

& 

i^S 

CJ 

£ 

1  j 

III  88888s8oM5-vft 

M 

^  ' 

J-2?    6666660066 

6 
II 

s 

j 

^ 

: 

4 

2        qOO^^OMOOOM 

o 

i 

i 

a     o      

J^'S  OOOOOOOOOO 

los    OOOOOOOOOO 

o 

0 

M 

| 

1 

11 

1.1 

•5 

0  rt 

*?  i    M   CM   co  ^"  to  vO   r^  oo   ON  O 

35 

Table  XXIII.  shows  the  differences  between  osmotic 
and  gas  pressures  derived  from  Table  XXII.,  and  also  the 
differences  when  no  correction  is  made  for  loss  in  rotation. 

Table  XXIIL — Differences  between   Osmotic  and  Gas  Pressure. 

Series  II. 


Weight- 
normal 

If  all  loss 
in  rotation 

If  one  half 
the  loss  in 
rotation 

If  all  loss 
in  rotation 
is  ascribed 

concentra- 
tion. 

is  ascribed 
to  inversion. 

is  ascribed 
to  dilution. 

to  subsequent 
dilution. 

0, 

I 

O 

•  13 

0, 

13 

0 

•  13 

0. 

2 

0 

,20 

0 

20 

O 

.20 

O 

3 

0 

.26 

0 

,26 

0 

.26 

0 

4 

o 

•33 

0 

•33 

0 

•33 

0 

5 

0 

.46 

O 

•47 

O 

.46 

O 

6 

0 

.69 

0 

,69 

0 

.69 

0. 

7 

0 

93 

0 

94 

0 

•93 

0 

8 

I 

.26 

I 

30 

I 

.28 

O 

9 

I 

•45 

I 

.56 

I 

•5i 

I 

o 

I 

.87 

2 

.04 

I 

.96 

As  in  Series  I.,  Table  XXIV.  contains  the  ratios  of  the 
molecular  osmotic  pressures  to  the  molecular  gas  pressures, 
including  their  ratios  if  all  the  dilution  is  subsequent  to  the 
measurement  of  pressure. 

Table  XXIV. — Ratios  of  Molecular  Osmotic  Pressure  to  Molec- 
ular Gas  Pressure. 

Series  II. 


If  one  half 
Weight-                  If  all  loss                     the  loss  in 
normal                  in  rotation                      rotation 
concentra-               is  ascribed                    is  ascribed 
tion.                    to  inversion.                 to  dilution. 

If  all  loss 
in  rotation 
is  ascribed 
to  subsequent 
dilution. 

0.  I 

•053 

•053 

•053 

0.2 

0-3 
0.4 

•  043 
.038 
.036 

•043 
.038 
.036 

•043 
.038 
.036 

0-5 

0.6 

0.7 

0.8 

•039 
.050 
.058 
.068 

.040 
.050 
.058 

.070 

•039 
.050 
.058 
.069 

0.9 

I  .0 

.070 
.081 

•075 
.089 

1.073 
1.085 

It  has  been  stated  that  Series  II.   has  shown  that  most 
of  the  dilution  takes  place  when  the  cell  is  being  opened. 


36 

It  may  be  asked  then,  Why  should  any  correction  for  loss 
in  rotation  be  made,  since  any  dilution  arising  after  the 
measurement  has  been  made,  does  not  affect  the  osmotic 
pressure?  In  other  words,  why  should  not  the  actually 
observed  osmotic  pressure  be  the  true  one? 

Some  years  ago  Morse  and  Frazer  tested  all  their  sugar 
solutions,  both  before  and  after  a  measurement  had  been 
made,1  to  see  if  they  could  detect  inversion.  Fehling's 
solution  gave  negative  results  with  the  lower  concentrations. 
In  the  case  of  the  higher  concentrations,  however,  0.5  to 
i.o  normal,  inversion  was  detected,  but  it  was  never  sufficient 
in  quantity  to  justify  a  correction  of  more  than  0.05  of  an 
atmosphere.  At  this  time  they  were  inclined  to  believe 
that  it  was  safe  to  attribute  most  of  the  loss  in  rotation 
to  inversion. 

Somewhat  later2  they  were  of  the  opinion  that  most  of 
the  loss  in  rotation  could  be  ascribed  to  dilution.  With 
improved  methods  for  opening  the  cells,  the  loss  in  rotation 
decreased  rapidly  from  2.8  per  cent  in  the  second  series  of 
measurements  in  the  vicinity  of  20°,  to  0.93  per  cent  as  shown 
in  Series  I.  at  10°. 

If  the  loss  in  rotation  had  been  due  to  any  great  extent  to 
inversion,  it  is  difficult  to  see  why  there  should  have  been  any 
marked  decrease  in  the  loss  in  rotation.  That  is,  the  amounts 
of  inversion  for  any  one  concentration  in  the  different  series 
should  have  been  fairly  constant  if  the  pressures  actually 
obtained  for  that  concentration  agree,  as  they  have  done. 

With  the  use  of  the  hypodermic  needle  the  average  loss 
in  rotation  of  the  solutions  was  reduced  to  0.13  per  cent  in 
Series  II.  at  10°. 

For  the  sake  of  comparison  the  following  table  is  given 
showing  the  losses  in  rotation  of  Series  I.  and  II.,  the  former 
being  the  last  series  in  which  the  cells  were  opened  by  the 
old  method.3  The  second  column  in  both  series,  that  is, 
the  loss  in  rotation  calculated  in  atmospheres,  is  based  upon 
the  assumption  that  all  loss  in  rotation  is  due  to  inversion. 

1  Am.  Chem.  J.,  34,  31. 

2  Ibid.,  38,  42,  51;  37,  463;  38,  199. 

3  1 bid.,  34,  20. 


37 

Table  XXV.— Loss  in  Rotation. 
Series  I. 


Weight- 
normal 
concentra- 

I,oss in 
rotation. 

I,oss  in 
rotation. 

tion. 

Per  cent. 

Atmospheres. 

0. 

I 

0. 

39 

0. 

005 

0. 

2 

0. 

So 

0 

02 

O. 

3 

O. 

76 

O 

04 

0. 

4 

0. 

83 

0, 

06 

0. 

5 

I  . 

13 

0 

10 

O. 

6 

I. 

15 

O 

07 

O. 

7 

I  . 

26 

0 

15 

0. 

8 

.  . 

.  . 

O. 

9 

I  . 

0 

I  . 

12 

0 

19 

Av. 

=    0.93 

Series  II. 

Weight- 
normal 
concentra- 
tion. 

I<oss  in 
rotation. 
Per  cent. 

Loss  in 
rotation. 
Atmospheres5. 

O.I 

0.00 

0.00 

0.2 

0.00 

0.00 

o-3 

0.4 
0.5 

0.6 

0.00 
0.00 
O.O9 
0.00 

0.00 

o.oo 
0.005 

0.00 

o-7 
0.8 
0.9 

I  .0 

0.07 
0.17 
0.41 
0.56 

0.005 
0.025 
0.06 
0.09 

Av.  =  o.  13 

It  will  be  noticed  that  in  the  measurements  in  Series  II. 
at  10°,  with  the  exception  of  the  0.5  normal,  there  is  no  loss 
in  rotation  until  the  0.7  normal  is  reached.  It  may  be  noted 
here  that,  both  in  the  case  of  the  0.5  normal  and  of  the  0.7 
normal,  all  the  loss  in  rotation  occurred  in  one  of  the  deter- 
minations, there  having  been  no  loss  in  the  duplicates. 

Since  there  was  no  loss  in  rotation  from  the  o.i  to  the  0.5 
normal,  and  since  the  cells  from  the  0.5  normal  on,  were 
closed  in  the  same  way  as  for  the  lower  concentrations,  it 


38 

appears  probable  that  the  small  loss  observed  in  the  0.5, 
0.7,  0.8,  0.9  normal,  and  the  normal  solutions,  is  to  be  as- 
cribed in  part,  at  least,  to  inversion,  and  the  results  in  Tables 
I.  to  XX.,  inclusive,  have  been  so  corrected. 

In  Tables  XXI.  to  XXIV.,  inclusive,  the  results  have  been 
presented  in  three  ways:  (i)  as  corrected  for  inversion;  (2) 
as  corrected  if  one  half  the  loss  in  rotation  is  ascribed  to 
dilution;  and  (3)  without  any  correction  for  loss  in  rotation. 
It  is  believed  that  the  results  without  any  correction,  what- 
soever, are  the  nearest  approximations  to  the  true  osmotic 
pressures  of  the  solutions. 

CONCORDANCE  OF  THE  RESULTS. 

By  referring  to  Table  XXI.,  it  will  be  noticed  that  the 
differences  between  duplicate  determinations  of  the  in- 
dividual concentrations  is  in  all  cases  confined  to  the  second 
decimal  place.  This  is  a  degree  of  concordance  which  has 
not  been  reached  in  any  of  the  earlier  measurements  of  the 
osmotic  pressure  of  cane  sugar  solutions,  and  is  due  to  the 
improvements  in  methods  which  have  already  been  dis- 
cussed. 

MOLECULAR  RATIOS. 

Notwithstanding  the  belief  that  the  actually  observed 
osmotic  pressures  are  more  accurate  than  those  corrected  for 
loss  in  rotation,  the  pressures  corrected  for  inversion  and  for 
half  dilution  give  practically  the  same  ratios  of  molecular 
osmotic  pressure  to  molecular  gas  pressure  as  the  uncorrected 
pressures.  This  concordance  is  due  to  the  small  loss  in  rota- 
tion. This  close  agreement  in  the  ratios,  whatever  the 
method  of  correcting  the  results,  will  be  seen  in  Table  XXIV. 

Even  if  half  of  the  loss  in  rotation  should  be  ascribed  to 
inversion,  the  largest  difference  in  the  molecular  ratios  of 
osmotic  to  gas  pressure  would  be  only  0.004  in  the  case  °f  the 
normal  concentration,  while,  up  to  the  0.8  normal,  the  two 
ratios  thus  calculated  would  be  identical. 

By  referring  to  Table  XXIV.,  it  will  be  observed  that  in  a 
general  way  up  to  the  0.6  normal  the  excess  of  osmotic  over 


39 

gas  pressure  is  about  4  per  cent.,  while,  from  that  point  on, 
the  excess  of  osmotic  over  gas  pressure  increases  until  in  the 
normal  solution  it  reaches  about  8.5  per  cent.  This  is  quite 
analogous  to  relations  observed  in  measurements  at  other 
temperatures,  also  to  those  observed  among  the  freezing 
points  of  cane  sugar  solutions. 

The  molecular  ratios  are  all  lower  than  those  obtained  in 
the  two  previous  series  at  lower  temperatures — those  in  the 
vicinity  of  o°  l  and  4°.2  There  is  the  usual  minimum  at  the 
0.4  normal  likewise  observed  at  this  same  concentration  in 
the  vicinity  of  o°  and  20 °.3 

The  uncorrected  osmotic  pressures,  however,  are  higher 
in  Series  II.  at  10°,  than  in  the  vicinity  of  o°  and,  with  a  few 
exceptions  in  the  lower  concentrations,  than  in  the  vicinity 
of  4°.  This  same  fact  appears  in  the  series  at  i5°.4  These 
results  would  seem  to  dispose  of  the  question  of  a  minimum 
in  the  osmotic  pressure  of  cane  sugar  solutions  between  o° 
and  20°. 

TEMPERATURE  COEFFICIENT. 

Evidences  of  a  decided  temperature  coefficient  in  the 
osmotic  pressure  of  cane  sugar  solutions  will  be  seen  when 
one  compares  Series  III.,  IV.  and  V.  in  Table  XXVI.  The  three 
columns  of  the  different  series  contain  the  osmotic  pressures 
without  any  correction  for  loss  in  rotation.  The  reason  for 
thus  calculating  the  pressures  need  not  be  repeated. 

It  will  be  observed  that  the  total  pressures  of  the  in- 
dividual series  increase  from  Series  III.  to  Series  IV.  and  from 
Series  IV.  to  Series  V.  The  rise  from  Series  III.  to  IV.  is  0.97 
atmosphere  while  that  from  Series  IV.  to  V.  is  2.07  atmos- 
pheres. 

1  Am.  Chem.  J.,  38,  207. 

2  Ibid.,  38,  207. 

3  Ibid.,  38,  207. 

<  Ibid.,  40. 


4o 

Table  XXVI. — A    Comparison  of  Series   V.   with  Series  HI. 

and  IV. 

Series  III.  Series  IV.              Series  V. 

Concentration.              Pressures.  Pressures.  Pressures. 

o°  4°-5°.                                 10°. 

O.I                                2  . 42  2 . 40                             2 . 44 

0.2                                4.79  4.75                             4.82 

0.3                                7.II  7.07                             7.19 

o-4                       9-35  9-43                     9-5§ 

0.5                     H-75  11.82  12.00 

0.6                     14.12  14.43  14-54 

0.7                     16.68  16.79  17-09 

0.8                     19.15  19.31  19.75 

0.9                     21.89  22.15  22.28 

i.o                     24.45  24.53  25.06 


Total  pressure  131-71  132.68  134-75 

Difference  o .  97  2.07 

Mean  molecular 

osmotic  pressure      23.95  24.12  24.50 

Difference  0.17  0.38 

Percent  0.71  1.58 

Mean  molecular 

gas  pressure  22.29  22.65  23.09 

Difference  o .  36  o .  44 

Per  cent  i .  62  i .  94 

The  mean  molecular  osmotic  pressures  are  obtained  by 
dividing  the  total  pressures  of  the  several  series  by  the  sum 
of  the  concentration  units  (5.5). 

The  mean  molecular  osmotic  pressures  thus  obtained  for 
the  three  series  in  the  table  rise  from  23.95  atmospheres 
(Series  III.)  to  24.50  atmospheres  (Series  V.)-  The  rise  is 
about  twice  as  great  (0.38  atmosphere)  from  4°-5°  to  10°, 
as  from  o°  to  4°-5°  (0.17  atmosphere).  About  the 
same  rise  takes  place  from  10°  to  15 01  as  from  4-5° 
to  10°.  Thus  with  rise  in  temperature  there  is  an  increase 
in  the  mean  molecular  osmotic  pressure. 
|^The  rise  in  mean  molecular  gas  pressure  from  o°  to  4°-5° 
is  0.36  atmosphere  while  that  from  4°-5°  to  10°  is  0.44 
atmosphere.  This  fact  shows  that,  while  the  rise  in  mean 
molecular  gas  pressure  from  o°  to  4°-5°  is  1.62  per  cent 

1  Am.  Chem.  J.,  40, 


and  that  from  4°-5°  to  10°  is  1.94  per  cent,  an  increase  of 
0.32  per  cent,  the  rise  in  mean  molecular  osmotic  pressure 
from  o°  to  4°-5°  is  0.71  per  cent,  and  from  4°-5°  to  10°  is 
1.58  per  cent,  an  increase  of  0.87  per  cent.  That  is,  the 
mean  molecular  osmotic  pressure  from  o°  to  4°-5°  appears 
to  increase  only  0.44  as  fast  as  the  mean  molecular  gas  pres- 
sure, while  from  4°-5°  to  10°  it  increases  o  .81  as  fast  as  the 
mean  molecular  gas  pressure. 


BIOGRAPHY. 

The  writer  was  born  in  Baltimore,  Md.,  February  18, 
1883.  He  received  his  early  education  in  the  public  schools 
of  that  city  and  the  degree  of  A.B.  from  Johns  Hopkins 
University  in  1905. 


RETURN  TO  the  circulation  desk  of  any 

University  of  California  Library 

or  to  the 

NORTHERN  REGIONAL  LIBRARY  FACILITY 
Bldg.  400,  Richmond  Field  Station 
University  of  California 
Richmond,  CA  94804-4698 

ALL  BOOKS  MAY  BE  RECALLED  AFTER  7  DAYS 
2-month  loans  may  be  renewed  by  calling 

(510)642-6753 
1-year  loans  may  be  recharged  by  bringing  books 

to  NRLF 
Renewals    and    recharges    may    be    made    4    days 

prior  to  due  date 

DUE  AS  STAMPED  BELOW 


FEB     9  1996 


20,000  (4/94) 


